Marlene Joyce Wales, 81, from Newmarket, died at the scene after the Honda CR-V she was travelling in veered off the A1066 at Shadwell, near Thetford, on April 17 last year.

Norfolk Coroner’s Court heard Mrs Wales was travelling with her husband, Philip, and their granddaughter, Alice Wales, when the tragedy happened at about 11.41am.

Mr Wales, who was in court for the hearing, said in a statement that he had been left "heartbroken and devastated" by the death of his wife.

The 88-year-old driver was heading to a caravan park in Kessingland (Image: James Bass)

The family had collected their granddaughter and were travelling towards Kessingland in Suffolk for a caravan holiday, with the car also carrying the family’s Labrador and a rabbit in a crate.

Forensic collision investigators said driving conditions were good, with sunny, dry weather and clear visibility along the long, straight stretch of road, which has a 60mph speed limit.

The Honda was travelling northeast towards Diss when investigating officers said it failed to negotiate a gentle right-hand bend about 125 metres before a junction.

Tyre marks showed the vehicle left the carriageway, entered a ditch, rotated and rolled before coming to rest on its roof against a tree.

Mrs Wales, who was in the front passenger seat, suffered a fatal neck fracture and died at the scene, shortly after her granddaughter heard her say she couldn't breathe.

A vehicle examiner confirmed there were no mechanical defects that could have caused the crash and that all occupants had been wearing seatbelts.

Alice, who was sitting in the rear seat, told officers: “I remember seeing the white line and then being in the ditch.”

She managed to kick a door open, escape the overturned vehicle and run to the road to flag down passing motorists for help.

Emergency services arrived quickly, but despite efforts by police and paramedics, Mrs Wales was pronounced dead at 12.23pm.

Dashcam footage from another driver showed the Honda being driven erratically shortly before the collision, drifting within its lane several times, causing the other driver to take evasive action.

The witness told police: “The vehicle was swerving a little like the driver was distracted or something wasn’t right. I backed off because I wasn’t able to overtake.”

He added: “I thought he might be on the phone, but when I passed I could see it was an elderly driver.”

Mr Wales later told police he had been wearing his prescription glasses, had slept well and was not using a phone or distracted by anything inside or outside the vehicle.

However, he was unable to read a number plate at the required distance during a later eyesight test, managing to do so only when nine metres away rather than the required 20 metres.

The court heard it was possible he may briefly have been distracted looking in his rear view mirror to speak to his granddaughter while mentioning a junction previously used when visiting caravan sites, though investigators said there was no direct evidence explaining why the car left the road.

Questions were also raised by a family member about whether the granddaughter’s rabbit, which was being transported in the car, could have escaped and distracted the occupants.

Assistant coroner Simon Milburn dismissed this suggestion, telling the court it was “complete speculation” and there was no evidence the animal played any part in the collision.

A family member also questioned the medical cause of death, saying: “A broken neck doesn’t kill you.”

But the coroner said the medical evidence was clear, telling the hearing: “The pathologist was clear that the cause of death was a fractured neck.”

Recording a conclusion of road traffic collision, Mr Milburn said: “For reasons which remain unclear, the vehicle left the carriageway and came to rest on its roof.”

He added that although there was evidence of "erratic driving" shortly beforehand, there was no evidence of mechanical failure or poor road conditions.

Mrs Wales died as a result of injuries sustained in the crash, he concluded.

The coroner offered condolences to the family at the conclusion of the hearing.

© Eastern Daily Press